On the one hand, the invention relates to device for cutting discarded pile loop weft yarns in a fabric that is composed of a backing fabric consisting of weft yarns and warp yarns, and that comprises pile warp yarns by which, in one or several zones, pile loops over discarded pile loop weft yarns are formed, whereas the device is provided with a cutting blade to cut the discarded pile loop weft yarns.
On the other hand, the invention relates to a weaving machine that is provided with such device. The device according to the invention can be either a single-piece weaving machine or a face-to-face weaving machine.
To weave pile loops in fabrics, two procedures are commonly used:                In one method, the pile loops are shaped by introducing weaving rods in the direction of the weft, over which the loop pile is laid. Then, after one or several beats of the reed, the weaving rod is pulled out of the fabric and the pile forms a loop.        In the other method, lancets are installed in the direction of the warp that serve as spacers to carry a discarded weft yarn that is introduced as a pile loop weft yarn, over which the loop pile is laid. After the thus shaped part of the fabric has left the top of the lancet, the discarded pile loop is removed from the fabric and the pile forms a loop.        
In the second procedure, removal of the discarded pile loop weft yarn can be performed in several ways, for instance by inserting a weft yarn made of yarn material that can be washed out of the fabric by a washing process. More commonly, the discarded pile loop weft yarn is removed from the fabric by pulling the discarded pile loop weft yarn out of the fabric. In such process, we pull for instance at the selve edge in which the discarded pile loop weft yarn is attached, or we use extra gripping devices to pull the discarded pile loop weft yarn out of the formed fabric, as is for instance described in BE 1 014 269. When this procedure is applied to larger weaving widths (more than 2 m), it is also a common practice to cut the discarded pile loop weft yarn in the middle of the fabric, and the thus created two parts of the discarded pile loop weft yarn are pulled out from both sides of the weaving machine. In the figures of BE 1 014 269, a knife is positioned in the centre at the fabric side and facing the lancets, in order to cut the discarded pile loop weft yarns in their middle. However, the text of BE 1 014 269 does neither specify how this is accomplished, nor how the device is built. As can be deducted from the first figure, this happens shortly after the fabric edge has been formed and beyond the point where the fabric leaves the lancets.
EP 1 347 087 describes a procedure and device for weaving fabrics with pile loops in face-to-face mode, in which the discarded pile loop weft yarn is severed by a cutting blade that is incorporated in one of the lancets in the centre of the weaving width. Such cutting lancet is present both in the row of the upper spacers and in the row of the lower spacers.
This procedure has a significant number of drawbacks.
The cutting of the discarded pile loop weft yarn takes place between the upper fabric and the lower fabric, completely out of the weaver's sight.
Replacing the cutting blade in the lancet is rather complicated because the entire lancet must be dismounted and reinstalled for this, which could lead to possible damage of the surrounding warp yarns.
In addition, it is difficult to observe and difficult to detect if cutting of the discarded pile loop weft yarn has failed for one or the other reason.
When the weaver is working with his hands in the vicinity of the top of the cutting lancets, which he only can see with great difficulty, he runs the risk of injuring himself on the cutting blades.
In addition, it often occurs that the cutting lancet provided for cutting of the discarded pile loop weft yarn for the upper fabric, which, most of the times, is located in a different reed dent than the one provided for cutting of the loop weft in the bottom fabric, cuts both the discarded pile loop weft yarn for the top fabric and the discarded pile loop weft yarn for the bottom fabric. In this case, when the discarded pile loop weft yarn is pulled out from both sides, a small piece of the discarded pile loop weft yarn remains behind in the middle of the fabric, which either can come loose at a later moment or create an uneven effect in the fabric, or both.